preparation of biodegradable composite starch/tragacanth gum/nanoclay film and study of its physicochemical and mechanical properties

in this study, biodegradable composite starch/tragacanth gum/nanoclay (st/tg/clay) film was prepared. the basis of the film was wheat starch, which tragacanth gum was added at three levels (0.2 and 0.5% by w/w) and clay nanoparticles at three levels (0.1, 0.5 and 3% by w/w). physicochemical properties of the film, including thickness, water solubility, moisture content, and vapor vapor permeability (wvp), were investigated. the mechanical properties of the films, including the tensile strength and elongation of the films, and the color characteristics of the films were examined. the results showed that adding tragacanth to the starch film increased the thickness, moisture content and permeability of the water vapor and reduced its solubility. the addition of tragacanth to the starch film increased tensile strength and elongation. the addition of tragacanth reduced the transparency of the films. adding clay nanoparticles to starch film increased the water content, reduced water vapor permeability, and reduced solubility, but adding nanoparticles increased the thickness. nanoclay increased the tensile strength of the films and reduced the elongation. the lightness of the films decreased with the addition of nano-clay, and the factor b, which indicated the yellowness of the film, increased. in general, it can be concluded that the addition of tragacanth and nanoclay improves the physical and mechanical properties of starch film.